Towards integrated quantum optical circuits using silicon photonics technologies

Nobuyuki Matsuda, Hiroki Takesue

Abstract Integrated quantum photonics is now seen as one of the promising approaches to realize scalable quantum information systems. With optical waveguides based on silicon photonics technologies, we can realize quantum optical circuits with a higher degree of integration than with silica waveguides. In addition, thanks to the large nonlinearity observed in silicon nanophotonic waveguides, we can implement active components such as entangled photon sources on a chip. In this paper, we report recent progress in integrated quantum photonic circuits based on silicon photonics. We review our work on correlated and entangled photon‐pair sources on silicon chips, using nanoscale silicon waveguides and silicon photonic crystal waveguides. We also describe an on‐chip quantum buffer realized using the slow‐light effect in a silicon photonic crystal waveguide. As an approach to combine the merits of different waveguide platforms, a hybrid quantum circuit that integrates a silicon‐based photon‐pair source and a silica‐based arrayed waveguide grating is also presented.

Yasutomo Ota, Ryota Katsumi, Alto Osada +4 more

Jonathan C. F. Matthews, Alberto Politi, André Stefanov +14 more

Mihai D. Vidrighin

PsiQuantum’s goal is to build the first useful quantum computer. Our approach is based on a scalable fault tolerant architecture that can be implemented using integrated photonics circuits connected by low loss optical fiber. We are developing the technology required for the photonics circuits in a commercial silicon foundry. We will discuss the fusion-based quantum computing architecture and highlight some of the technologies that have been developed by the company.

Jonathan C. F. Matthews, Alberto Politi, Anthony Laing +12 more

Alberto Politi, Martin James Cryan, John Rarity +2 more

Quantum technologies based on photons will likely require an integrated optics architecture for improved performance, miniaturization, and scalability. We demonstrate high-fidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits, including two-photon quantum interference with a visibility of 94.8 +/- 0.5%; a controlled-NOT gate with an average logical basis fidelity of 94.3 +/- 0.2%; and a path-entangled state of two photons with fidelity of >92%. These results show that it is possible to directly "write" sophisticated photonic quantum circuits onto a silicon chip, which will be of benefit to future quantum technologies based on photons, including information processing, communication, metrology, and lithography, as well as the fundamental science of quantum optics.